1. Field of the Invention
The present invention relates generally to means and methods for attaching devices to each other, more particularly to attaching electronic devices and packages on to each other, or on to substrates or Printed Circuit Boards (PCBs), etc. The invention relates to both leadless packages, such as BGAs or LCCCs, as well as to leaded packages, such as DIPs.
The invention further relates to the reliability and long operating life of assemblies incorporating such devices, and more specifically, when such assemblies are exposed to harsh operating or environmental conditions, such as power cycling or thermal cycling, and more specifically yet, when the different components of such assemblies have different Thermal Coefficients of Expansion (TCEs), what is referred to TCE Mismatch.
Furthermore, the invention relates to the connecting means, such as leads, legs, solder joints and the like, both for the leadless as well as the leaded devices, and the shape and orientation/positioning of these connecting means, especially as to how all this would affect the reliability and long operating life of such assemblies, especially when exposed to the above mentioned operating conditions.